The low-lying level structure of the unbound system $^{16}$B has been investigated via single-proton removal from a 35 MeV/nucleon $^{17}$C beam. The coincident detection of the beam velocity $^{15}$B fragment and neutron allowed the relative energy
of the in-flight decay of $^{16}$B to be reconstructed. The resulting spectrum exhibited a narrow peak some 85 keV above threshold. It is argued that this feature corresponds to a very narrow ($Gamma ll $100 keV) resonance, or an unresolved multiplet, with a dominant $pi (p_{3/2})^{-1} otimes u (d_{5/2}^3)_{J=3/2^+}$ + $pi (p_{3/2})^{-1} otimes u (d_{5/2}^2,s_{1/2})_{J=3/2^+}$ configuration which decays by d-wave neutron emission.
